The rumored drop of the headphone port on the iPhone may not be as painful as some feared.According to The NPD Group, Bluetooth headphones accounted for 54 percent of U.S. dollars sales for the first half of the year — the first time this has happened. Growth was spurred by decreasing average sales prices (ASPs): The ASP for the six-month period dropped 5 percent vs. the prior-year period. Almost 30 percent of Bluetooth headphones sold in the 2016 period were $50 or less; just 16 percent could say the same last year.Bluetooth headphones saw a 42 percent year-over-year increase in dollar sales for the six-month period, while the overall headphones category saw a 7 percent increase.Despite this growth, however, Bluetooth models accounted for just 17 percent of U.S. unit sales. This can be attributed to the sheer overwhelming number of low-priced wired headphones in the market, Ben Arnold, NPD executive director, industry analyst, confirmed with TWICE. The ASP for Bluetooth headphones was $98 for the last 12 months, while the ASP for non-Bluetooth was just $18.73.